Fabrication of TiAlNb alloy sheet by sintering pure metal foils

Ti-Al-Nb ternary intermetallic alloy sheet was fabricated by sintering pure metal foils of Ti, Al and Nb(foil-foil method). The phase evolution during sintering process and the final microstructure were analyzed by various techniques, including Back-scattered Electron Image (BEI), X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS), etc. Results reveal that the structure evolution in the sintering processes is very complex and strongly depends on the sintering conditions, especially depends on whether or not the occurrence of the self-propagating high-temperature synthesis (SHS) during sintering. When sintered at relatively lower temperature, the alloy sheets are composed of multi phases of Nb2Al (sigma), Nb3Al (delta), Ti3Al (alpha(2)) and TiAl (gamma) in a lamellar form. Sintered at higher temperature and annealing for sufficient long time, the sheet is composed of uniform structures mainly containing Ti2AlNb (O phase) and solid solution (beta).